FIG. 7 is a side view illustrating a wireless device attached with a conventional antenna device. Wireless device 1 is attached with so-called rod-type antenna device 10. Antenna device 10 is composed of antenna base 12 and antenna rod 11. At a tip end of antenna rod 11, knob section 11A is provided. Antenna base 12 is provided, for example, at a side face of wireless device 1 having a box body or a chassis so that antenna base 12 protrudes from the side face. Antenna base 12 is connected to antenna rod 11 via hinge mechanism 15. Hinge mechanism 15 allows antenna rod 11 to be turned in turning direction 11B.
FIG. 8 is a perspective view of the wireless device attached with antenna device 10 as shown in FIG. 7. In FIG. 8, the same components as those of FIG. 7 are denoted with the same reference numerals.
FIG. 9 is an exploded perspective view of hinge mechanism 15 shown in FIG. 7 and FIG. 8. Hinge mechanism 15 includes connection plate 11B that is provided at the lower end of antenna rod 11 and that has a flat plate-like shape formed in a protruded manner. Hinge mechanism 15 also includes: a pair of sandwiching plates 12A that sandwich both side faces of connection plate 11B and that are provided at the tip end of antenna base 12; and axial support pin 16 that is inserted into penetration holes 12B and 11C provided in sandwiching plate 12A and connection plate 11B and that allows antenna rod 11 to be turned around or fixed to antenna base 12.
At front and back faces of connection plate 11B, convex sections 17 are separately provided, respectively. At the respective inner faces of sandwiching plates 12A, first concave sections 18A are provided. Convex sections 17 are fitted into first concave sections 18A when antenna rod 11 is turned in the same direction as that of the center line of a direction along which antenna base 12 extends. At the respective inner faces of sandwiching plates 12A, second concave sections 18B are also provided. Convex sections 17 are fitted into second concave sections 18B when antenna rod 11 is turned to a position at which antenna rod 11 is upwardly orthogonal to the direction along which antenna base 12 extends.
When not in use, antenna rod 11 is turned via hinge mechanism 15 to a position in the same direction as that along which antenna base 12 extends. At this position, convex sections 17 of hinge mechanism 15 are fitted into first concave sections 18A. Thus, antenna device 10 can be stored in wireless device 1 along telescopic direction 11C except for knob section 11A of the tip end of antenna rod 11.
When antenna device 10 is to be used, antenna rod 11 and antenna base 12, which are stored so that the center lines thereof are on a single straight line, are pulled out from wireless device 1 by grabbing and pulling knob section 11A. As a result, as shown in FIG. 7 and FIG. 8, antenna rod 11 is turned in a direction that is upwardly orthogonal to the direction along which antenna base 12 extends. Specifically, antenna rod 11 is turned in turning direction 11B so that antenna device 10 is used in a fixed condition in which convex sections 17 of hinge mechanism 15 are fitted into second concave sections 18B, respectively.
Conventional antenna device 10 as described above has been structured so that convex sections 17 of hinge mechanism 15 are respectively fitted into concave section 18A and 18B to allow antenna rod 11 to stop at a position with a predetermined angle. However, this structure causes, when convex sections 17 are respectively moved between concave sections 18A and concave sections 18B, convex sections 17 to move while respectively being abutted with opposed inner surfaces of sandwiching plate 12A. This causes wear of convex sections 17 and concave sections 18A and concave sections 18B, respectively. An increased frequency at which antenna device 10 is used in particular increases the wear of convex sections 17 and concave sections 18A and concave sections 18B, which finally causes an inconvenience where antenna rod 11 cannot be fixed to antenna base 12 at a predetermined position. Japanese Patent Unexamined Publication (Japanese Patent Application No. 5-55817) is known as a background art document.